Apparatus and methods are known for accessing a patient's vasculature percutaneously, e.g., to perform a procedure within the vasculature, and for sealing the puncture that results after completing the procedure. For example, a hollow needle may be inserted through a patient's skin and overlying tissue into a blood vessel. A guide wire may be passed through the needle lumen into the blood vessel, whereupon the needle may be removed. An introducer sheath may then be advanced over the guide wire into the vessel, e.g., in conjunction with or subsequent to one or more dilators.
A catheter or other device may be advanced through the introducer sheath and over the guide wire into a position for performing a medical procedure. Thus, the introducer sheath may facilitate introducing various devices into the vessel, while minimizing trauma to the vessel wall and/or minimizing blood loss. Upon completing the procedure, the device(s) and introducer sheath may be removed, leaving a puncture extending between the skin and the vessel wall.
To seal the puncture, external pressure may be applied to the overlying tissue, e.g., manually and/or using sandbags, until hemostasis occurs. This procedure, however, may be time consuming and expensive, requiring as much as an hour of a medical professional's time. It is also uncomfortable for the patient, and may require the patient to remain immobilized in the operating room, catheter lab, or holding area. In addition, a risk of hematoma exists from bleeding before hemostasis occurs.
Various apparatus and methods have been suggested for sealing a percutaneous puncture instead of using external pressure. For example, U.S. Pat. No. 5,108,421 issued to Fowler discloses a plug that may be delivered into a puncture through tissue. In one embodiment, a catheter is inserted through the puncture into the blood vessel. A balloon on the catheter is expanded and retracted until the balloon is disposed adjacent the puncture at the wall of the vessel. The plug may be advanced into the puncture until the plug contacts the balloon. Once the plug is positioned within the puncture, the balloon may be deflated and withdrawn, leaving the plug therein to expand and seal the puncture and/or to promote hemostasis.
Alternatively, U.S. Pat. No. 5,222,974 issued to Kensey et al. describes a system and method for sealing a percutaneous puncture in an artery. The system includes a sealing member including a resorbable plug, a rigid resorbable anchor member, and resorbable positioning member in the form of a filament. The disclosed sealing member is designed to resorb completely, e.g., within sixty to ninety (60-90) days.
U.S. Pat. No. 6,663,655 issued to Ginn et al. discloses a two-piece plug device for sealing a passage through tissue. The device includes a plug member and a sealing member disposed within a lumen of the plug member. The device is delivered into a puncture proximate to a vessel communicating with the puncture. The plug member and sealing member are made of a bioabsorbable material and may remain within the body until both components are absorbed.
U.S. Pat. No. 5,916,236 issued to Muijs Van de Moer et al. discloses an occlusion assembly that includes a flexible sheet attached to one end of a thread, and a retaining ring slidable along the thread towards the sheet. The sheet is folded, delivered via a sheath through a puncture into a blood vessel, and allowed to unfold within the vessel. The thread is pulled to direct the sheet against the wall of the vessel, whereupon the retaining ring is advanced down the thread to secure the sheet against the wall. The sheet, thread, and retaining ring are made of bioabsorbable material such that they disappear after a few weeks.
U.S. Pat. No. 4,890,612 issued to Kensey discloses a three-component closure device that includes a holding member or toggle, a filament, and a cylindrical plug made of bioabsorbable materials that is absorbed in approximately, forty five days, ninety days, and ten days, respectively. The closure device is delivered through a puncture into a blood vessel via a sheath, whereupon the filament is retracted to pull the toggle against the wall of the vessel with the plug within the puncture. The closure device remains in place until absorbed by the patient's body.
One of the disadvantages with these closure devices is that it may be difficult to position them properly with respect to the vessel, which may be significant since it is generally undesirable to expose collagen material to the bloodstream where it may float downstream and cause an embolism. In addition, these closure devices take a relatively long period of time to resorb and/or dissolve within the body (i.e., ten days or more). This is particularly undesirable for the portion of the device that is disposed within the blood vessel, because of the risk of a piece of the closure device breaking free and causing an embolism or other damage downstream of the puncture site.
Even when non-collagen materials are used for the portion of a closure device residing within a blood vessel, however, it may be desirable to minimize the amount of time the intravascular portion of the device is present within the vessel. Of course, if the device is absorbed too rapidly, it may adversely affect effective hemostasis of the puncture without risk of hematoma or other complications.